Socket and package power/ground bar apparatus that increases current carrying capacity resulting in higher IC power delivery

ABSTRACT

A socket and package apparatus are disclosed for increasing the amount of power that can be delivered from an IC board to an IC where the IC package is mounted in a socket connected to the IC board. The apparatus has two separable and distinct parts designed to electrically engage. The package is designed with a power bar where the panels of the power bar are permanently and electrically connected to various power planes of the IC package along its entire adjacent wall. The socket is designed with a power bar carrier designed to maximize the current flow from the IC board to the power bar. The package is then engaged into the socket.

COPYRIGHT NOTICE

[0001] Contained herein is material that is subject to copyrightprotection. The copyright owner has no objection to the facsimilereproduction of the patent disclosure by any person as it appears in thePatent and Trademark Office patent files or records, but otherwisereserves all rights to the copyright whatsoever.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates generally to the field of Surface MountTechnology (SMT) Package and Socket Designs. More particularly, theinvention relates to providing a power bar and power bar carrier forincreasing power and ground current throughputs between an IntegratedCircuit (IC) board and an IC chip while equalizing load and currentdistribution.

[0004] 2. Description of the Related Art

[0005] With the increased demand for computer functionality and speed,improvements are always being made in technologies that affect theability of an IC board to deliver power to components that reside on theIC board. Because of manufacturing concerns, package stress factors,cost of materials, etc., each generation of technological advancesprovide some benefit to the existing state of technology capability andprovides a segue into the next generation of technological innovation.With the advent of Surface Mount Technology (“SMT”), certain ICs thatmay be modified, coded or evolve in later generations, so that boardscontaining these ICs could be easily upgraded, created a practicalupgrade and replacement problem.

[0006] The solution to this problem resulted in sockets as place-holdersand carriages for these evolving ICs. The sockets are surface mountedonto the IC board during the solder re-flow and then the chips requiringsocket placement are easily placed and removed from the board whenrequired. As technologies have improved, the traces that connect thepower and ground sources of the IC board to the chip have become alimitation because ICs require increasingly more power delivered throughthe socket. For instance, present SMT socket sizes limit the number ofpins to about 800 pins. Of these 800 pins, many will be designated forI/O type signals and the rest are connected to either power or groundplanes. As technologies improved for development of the IC and morecomputational power is attained for any given IC, bottlenecks arecreated by pin limitations for supplying the power from the IC board tothese ever increasingly power hungry IC chips. The problem arisesbecause even though more pins are designated for power transfer, the pinnumber limitation and the pin and trace size limitation impose naturalrestrictions on the amount of current that can be transferred across aset of multiple pins designated to a power plane. One of the primarybottleneck limitations is generated by the chip pins and thecorresponding socket traces providing the power to those pins. Each pinlimits the current going through the pins to between one half of an ampto one amp. Additionally, the electrical power delivery performance islimited by the area where the package pin and socket trace make contact.Because of the limited size of each pin and its corresponding contactarea, the resulting resistance and inductance of the contact reduces thecurrent delivery for each pin or provides inconsistent power transferbetween one pin and another pin because of irregularities in thecontact.

[0007]FIG. 12 demonstrates a prior art socket 1210 engaging an ICpackage 1211. All of the package pins 1201 are inserted into and engagea socket's pin receptacles 1202. A lever 1203 is used for locking thesocket pins into place and forcing contact between the pins and theircorresponding receptacles. Because of the small size of the pins,limited force can be applied to the pins resulting in inconsistent powertransfer results. Additionally, each package pin and socket trace limitsthe amount of current that can be passed through the pin.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0008] The present invention is illustrated by way of example, and notby way of limitation, in the figures of the accompanying drawings and inwhich like reference numerals refer to similar elements and in which:

[0009]FIG. 1 is a high level depiction of a socket and an IC packageaccording to one embodiment the invention.

[0010]FIG. 2 is a top view of a socket where several pin receptacles areelectrically connected.

[0011]FIGS. 3a and 3 b illustrate an IC package having a power baraccording to one embodiment of the invention.

[0012]FIG. 4 is a simplified socket according to one embodiment of theinvention.

[0013]FIG. 5 demonstrates how a package power bar may be mounted in asocket carrier according to one embodiment of the invention.

[0014]FIG. 6 is a socket with a cross-sectional view of a power baraccording to one embodiment of the invention.

[0015]FIGS. 7a and 7 b demonstrate a carrier engaging a power baaccording to one embodiment of the invention r.

[0016]FIG. 8 is an example of how a carrier side may be stamped from anelectrically conducting foil according to one embodiment of theinvention.

[0017]FIG. 9 illustrates how two foils may be mounted with insulation toform a carrier according to one embodiment of the invention.

[0018]FIGS. 10 and 11 show alternative activation mechanisms for acarrier to engage a power bar according to one embodiment of theinvention.

[0019]FIG. 12 provides a prior art socket engaging a prior art package.

[0020]FIG. 13 is a top view of a prior art socket.

DETAILED DESCRIPTION OF THE INVENTION

[0021] An IC socket and corresponding IC package are described forincreasing the ability to transfer power from an IC board to an IC. Theapparatus encompasses a socket including a power bar carrier. The powerbar carrier receives a corresponding power bar incorporated on the ICpackage.

[0022] In the following description, for the purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the present invention. However, the present inventionmay be practiced without some of the specific detail provided therein.The invention is described herein primarily in terms of a SMT socketdesigned to receive an IC with at least one power bar. The power barimproves current transfer while reducing contact resistance andinductance created by current power pin contact sizes.

[0023] The invention, however, is not limited to this particularembodiment alone, nor is it limited to use in conjunction with anyparticular combination of pins and power bars nor is it limited to usein SMT environments. For example, the claimed apparatus may be used inconjunction with any IC board where utilization of a power barmanufactured package improves power delivery to the IC and the boardassembly technology supports it.

[0024] Detailed Description

[0025]FIG. 1 illustrates a high level depiction of socket and IC packageaccording to one embodiment of the invention. An IC package 101 having apower plane (not shown) is mounted into a socket 103. The IC package 101has multiple input/output pins 104 that are inserted into correspondingsocket holes 105 for transferring and receiving informationalinput/output (I/O) signals necessary for the proper functional operationof the IC chip 106 integrated with the IC package 101. Although otherelectrically conductive materials may be used, in this embodiment aCopper (Cu) Power Bar 107 is connected to the power plane 102 along itsentire adjacent border 108 and extrudes from the IC package to beinserted into a corresponding power bar carrier 109 incorporated in thesocket 103. A locking mechanism 110 is employed to force the I/O the pinreceptacle contacts to make contact with their corresponding pins, whilea second locking mechanism 111 may be employed to separately lock thepower bar carrier to the power bar.

[0026]FIG. 13 is a top view of a prior art socket 1310 (the view fromwhich the package would engage the socket) containing multiple pinreceptacles 1311 that connect to pads for surface mounting on theunderside of the socket. The pin receptacles 1311 each have acorresponding contact 1312 for receiving and abutting to the packagepins when the IC package is engaged into the socket. An insulatedsocket-housing barrier 1313 prevents any contact between any of the pins1311 and their respective contacts 1312 with any adjacent pin. The pinsize has been reduced over time due to chip complexity, solder re-flowand packaging advances such as SMT and C4 technologies. Increasedfunctionality has resulted in increased power dissipation demands by theIC device to the point where power and ground must be supplied throughmultiple pins. However, the pin size and the contacts between the socketpin receptacle and the package pin limit the power that may be suppliedto an IC from an IC board. Additionally, the individual pins cause highnon-uniform current distribution between the different pins that areutilized to supply the power to the IC package.

[0027] While FIG. 13 demonstrates the present state of the art, FIG. 2conceptually demonstrates a portion of the philosophy behind theinnovative socket and corresponding package enhancements from the socketperspective. Several pin receptacles 221 or contacts 222 designated forpower transfer are electrically bound together by a shorting piece ofcopper 223. Although the shorting piece of copper is shown here as atrace for demonstration purposes, one embodiment contemplates severalpins and their shorting piece constructed from a single copper foil soas to maximize the current surface area and distribution path. The pinsmay be connected in any configuration that makes sense for the design ofthe IC package. To accommodate the increased current capability of thenew socket design, the IC package should also be modified so that abottleneck does not occur in the pins transferring the power from thesocket to the IC.

[0028] Multiple socket pin receptacles 225, that include I/O pinreceptacles or other pin receptacles where current throughput is notcrucial, are connected to multiple IC package pins, socket traces andcontacts. Currently, each IC package pin's known current carryingcapacity, whether limited by the socket pin receptacle or the IC packagepin, is between 0.5 amps and 1 amp. Because pin utilization is wellknown in the art, a complete discussion of their construction andimplementation is omitted.

[0029] An illustrative IC Package contemplated by the invention is shownin more detail in FIGS. 3a and 3 b. Although various planes or crossplanes may exist in the package for holding the power and ground for theIC, FIG. 3a demonstrates two power planes, one for holding a firstvoltage level and one for holding a second voltage level. For simplicitythese voltages levels will be referred to as power and ground. Byconvention, the term “power” encompasses the notion of ground and thenomenclature verbalized with reference to power planes and power bars inthis invention does not deviate from that convention. Arbitrarily, thepower plane 301 resides above the ground plane 302 although it is wellunderstood that location is irrelevant. Additionally, a plane in thiscontext is one level of copper although a plane that is not restrictedto copper or a single level is contemplated. For example, a ground planecould be constructed of any conducting material and spread among severallevels in the IC package 303. The ground power plane's extrusion panel304 could connect directly to one or more of the ground planes along itsentire adjacent edge 311 to the ground plane.

[0030] In this embodiment, a power bar 310 comprises two power planeextrusion panels 304 and 305 that are separated by an insulating bufferpanel 306 for protecting the integrity of the power signals to bedelivered by preventing short circuiting. The ground power planeextrusion panel 304 is connected along its entire adjacent borderingedge 311 to the ground power plane 302 by solder or equivalent while thepower plane extrusion panel 305 is connected along its entire adjacentbordering edge to the power plane 301 via solder or equivalent. Aninsulation barrier panel 307 along the perpendicular circumference ofthe power plane extrusion panel 305 isolates the power plane extrusionpanel 305 from the ground plane 302 where the power plane extrusionpanel 305 penetrates or passes through the ground plane 302.

[0031] Each power or ground extrusion panel 304 or 305 of the power bar310 may have various contact extrusions, bumps or ridges to enableintentional engaging of the IC package power bar to a socket. In thisembodiment, several protrusions in the form of regularly spaced bumps orridges 309 are integrally connected and formed as part of the power orground extrusion panels to assist in the intentional engaging or lockingin place of the IC package power bar to the socket carrier.

[0032] The power bar removes the inherent limitations of transferringpower to an IC through pins by providing a larger surface and contactarea. The increased surface and contact area provides substantial powerdelivery capabilities while also providing a uniform delivery mechanismthat reduces resistance and inductance caused by multiple pins.

[0033]FIG. 4 illustrates a power bar carrier portion of a socketaccording to one embodiment where the carrier 410 has two electricallyconducting side panels 401 and 402 separated by a non-conductiveinsulation bar 403. The non-conductive insulating material may be formedfrom one mold or pieced together to hold the various conductive powerbar carriers and pin receptacles (not shown). In this embodiment, theelectrically conducting side panels 401 and 402 are separated byinsulation in order to accommodate both power and ground power planeextrusion panels 304 and 305 from a package power bar. Although thepower bar and the power bar carrier are shown to be a full length andstraight line design, the invention contemplates any shape of power barand corresponding power bar carrier. The power bar carrier and the powerbar are always designed to carry more current than the combination ofpins that it replaces. At a minimum, a power bar replaces two pins suchthat instead of having a bottleneck of the individual pins, the socketconfiguration need only have one power bar design such that a largersurface area exists where the surface area is inclusive of the size ofthe individual pins plus the space that would normally have beeninsulation between them. Optimally, although the design is not solimited, a power bar design accommodates the replacement for all pinsand pin receptacles that would normally be associated with a given powerplane in order to optimize current distribution, consistency and powerdelivery capability.

[0034] The socket may ultimately be placed on an IC board, such as aCentral Processing Unit (CPU) motherboard. As the design contemplatesuse in a solder-flow process used by existing technologies, such as SMT,the mounting pads 405 on the bottom of the socket are produced by knownmethods and are spaced as required.

[0035]FIG. 5 demonstrates how a power bar carrier may be mounted into asocket. The power bar 501 in this embodiment is made of several segments502, each designed to correspond with contact portions 503 of a carrier504. The power bar 501 is initially set into the carrier such that itbegins in a position where no contact is made. Upon sliding the powerbar into position, each of the segments align with their correspondingcontacts and the spring portion of the carrier's contacts apply theforce necessary to establish the electrical connection.

[0036]FIG. 6 depicts a socket 600 with several input/output (I/O) typepin receptacles 601 and a power bar carrier 602 that may be located inthe center of the socket 600. A cross-sectional view of a power bar 603detached from the package sitting in the carrier 602 is alsoillustrated. Although a power bar in which the entire surface of eachpower plane extrusion panel contacts the entire contact surface of itscorresponding electrically conducting carrier panel is contemplated,this embodiment has contact bumps 604 so that the package can engage thecarrier by a physical shift that aligns the carrier bumps with the powerbar bumps as demonstrated in FIG. 7a and 7 b.

[0037]FIGS. 7a and 7 b show a power bar 701 with power and ground planeextrusion panels 702 and 703 having contact bumps 704 and the extrudingcontact bumps or bent contact spring elements 705 of the carrier'scorresponding carrier foil. FIG. 7a shows the power bar before it isengaged with the socket carrier and FIG. 7b illustrates the power barengaged with the socket carrier bumps. Because the power bar may have adifferent alignment with the socket carrier than the I/O pins to the I/Opin receptacles, as demonstrated in FIG. 1, the engagement shift 111 forthe power bar may be performed independently of the I/O pin engagement110 for the package to the socket. For instance, two activationmechanisms may exist on the socket to engage the various types ofreceptacles. Similarly, a single activation mechanism (not shown) may beused to engage the package pins while another activation mechanismcapable of applying pressure in a different direction may cause thepower bar to engage with the carrier. A discussion of how an activationmechanism causes a socket to engage a corresponding package is omittedbecause such mechanisms are well known in the art. In order to deliverthe power efficiently, thereby reducing contact resistance andinductance, the shape of the contacts and the power bar can be differentfrom those utilized for the pins. By separating the activatingmechanisms, more contact force may be applied to the power deliverycontacts of the power bar mechanism to further improve electricalperformance. Although separate activation methods have been described, asingle activation mechanism that applies necessary force for the pinsand power bar's respective engagement is also contemplated.

[0038]FIG. 8 shows an example of how a copper or other electricallyconducting foil 800 may be stamped to produce one of the carrier'sconducting panels. In this example, carrier panel contacts 801 forconnecting to the power bar bumps are cut and bent to provide enoughtension to produce a frictional engagement of the power bar. This typeof bending of a conducting material is known to produce a springconstant that may be efficiently accessed in the type of engagementmechanism contemplated. The BGA pads are connected to extrusions 802stamped at the base of the foil to provide for a SMT soldering of thesocket to an IC board. Two foils 901 and 902 similar to those shown inFIG. 8 are sandwiched in an insulating material 903 along their mainconducting surfaces as shown in FIG. 9. The entire carrier is thenconnected into a power bar socket 904 which is then capable of receivinga corresponding power bar package 905.

[0039]FIGS. 10 and 11 demonstrate two alternative embodiments where thepower bar is engaged by a spring type mechanism, here a bent carrierpanel. In FIG. 10, a single spring 1001 applies the contact for onepower plane extrusion of the power bar while pressing the power bar intocontact with the other carrier side 1002. Alternatively, FIG. 11demonstrates a carrier employing two bent spring panels 1101 to engagethe respective panels of the power bar.

[0040] Alternative Embodiments

[0041] The foregoing description has demonstrated several embodiments ofthe invention. It is understood, however, that the invention need not belimited to any specific embodiment and that all examples are onlyillustrative. Numerous other embodiments that are limited only by thescope and language of the claims are contemplated as would be obvious tosomeone possessing ordinary skill in the art and having the benefit ofthis disclosure.

What is claimed is:
 1. An integrated circuit (IC) package comprising: a first power plane; and a power bar including a first conducting panel electrically connected to the first power plane along a first adjacent edge.
 2. The IC package of claim 1 wherein the IC package further includes a second power plane electrically isolated from the first power plane; and a second conducting panel electrically connected to the second power plane of the IC package along a second adjacent edge.
 3. The IC package of claim 2, wherein the power bar further includes a non-conducting insulation panel separating the first conducting panel from the second conducting panel.
 4. The IC package of claim 1, wherein the power bar further includes one or more conducting bumps electrically connected to the first conducting panel.
 5. The IC package of claim 3, wherein the power bar further includes one or more conducting bumps electrically connected to one or more of the first conducting panel and the second conducing panel.
 6. An Integrated Circuit (IC) socket comprising: a power bar carrier, wherein the power bar carrier includes a first conducting panel electrically coupled to a first plurality of conducting pads.
 7. The IC socket of claim 6, wherein the first conducting panel further includes one or more conducting contacts extending beyond the periphery of the conducting panel and coupled to the first conducting panel.
 8. The socket of claim 7 wherein the first conducting panel and the one or more conducting contacts are stamped from a single conducting foil.
 9. The IC socket of claim 7, wherein the one or more conducting contacts are compressibly and electrically engageable.
 10. The IC socket of claim 7, wherein the one or more conducting contacts are comprised of a bent conducting material.
 11. The IC socket of claim 7, wherein the one or more conducting contacts further comprise a spring constant.
 12. The IC socket of claim 6 wherein the power bar carrier further includes a second conducting panel electrically coupled to a second plurality of conducting pads.
 13. The IC socket of claim 12 wherein the second conducting panel is insulated from the first conducting panel.
 14. The IC socket of claim 6 further comprising an activation mechanism that causes the power bar carrier to engage a power bar of a corresponding IC package.
 15. The IC socket of claim 6 further comprising one or more pin receptacles.
 16. The IC socket of claim 15 further comprising a first activation mechanism that causes the power bar carrier to engage a power bar of a corresponding IC package with a first force and a second activation mechanism that causes the one or more pin receptacles to engage one or more pins with a second force.
 17. The IC socket of claim 16 wherein the first force and the second force are substantially equivalent.
 18. The IC socket of claim 15 further comprising an activation mechanism that simultaneously causes the power bar carrier to engage a power bar with a first force and causes the one or more pin receptacles to engage one or more pins with a second force.
 19. The IC socket of claim 18 wherein the first force and the second force are substantially equivalent.
 20. An integrated circuit (IC) power delivery system comprising: an IC socket including a power bar carrier comprising a first conducting panel electrically coupled to a first plurality of conducting pads; and an IC package including a first power plane and a power bar comprising a first conducting panel electrically connected to the first power plane along a first adjacent edge.
 21. The IC power delivery system of claim 20 wherein the IC package further includes: a second power plane electrically isolated from the first power plane; and a second conducting panel electrically connected to the second power plane of the IC package along a second adjacent edge.
 22. The IC power delivery system of claim 21, wherein the power bar further includes a non-conducting insulation panel separating the first conducting panel from the second conducting panel.
 23. The IC power delivery system of claim 20, wherein the power bar further includes one or more conducting bumps electrically connected to the first conducting panel.
 24. The IC power delivery system of claim 22, wherein the power bar further includes one or more conducting bumps electrically connected to one or more of the first conducting panel and the second conducing panel.
 25. The IC power delivery system of claim 20, wherein the first conducting panel further includes one or more conducting contacts extending beyond the periphery of the conducting panel and coupled to the first conducting panel.
 26. The IC power delivery system of claim 25 wherein the first conducting panel and the one or more conducting contacts are stamped from a single conducting foil.
 27. The IC power delivery system of claim 25, wherein the one or more conducting contacts are compressibly and electrically engageable.
 28. The IC power delivery system of claim 25, wherein the one or more conducting contacts are comprised of a bent conducting material.
 29. The IC power delivery system of claim 25, wherein the one or more conducting contacts further comprise a spring constant.
 30. The IC power delivery system of claim 20 wherein the power bar carrier further includes a second conducting panel electrically coupled to a second plurality of conducting pads.
 31. The IC power delivery system of claim 30 wherein the second conducting panel is insulated from the first conducting panel.
 32. The IC power delivery system of claim 20 further comprising an activation mechanism that causes the power bar carrier to engage a power bar of a corresponding IC package.
 33. The IC power delivery system of claim 20 further comprising one or more pin receptacles.
 34. The IC power delivery system of claim 33 further comprising a first activation mechanism that causes the power bar carrier to engage a power bar of a corresponding IC package with a first force and a second activation mechanism that causes the one or more pin receptacles to engage one or more pins with a second force.
 35. The IC power delivery system of claim 34 wherein the first force and the second force are substantially equivalent.
 36. The IC power delivery system of claim 33 further comprising an activation mechanism that simultaneously causes the power bar carrier to engage a power bar with a first force and causes the one or more pin receptacles to engage one or more pins with a second force.
 37. The IC power delivery system of claim 36 wherein the first force and the second force are substantially equivalent. 